Setting the Scrollbar Thumb size

Question

I am attempting to work out the algorithm associated with sizing of the WPF Scrollbar thumb element.

The thumb element can be sized using the Scrollbar.ViewportSi

Answer 1

From: http://msdn.microsoft.com/en-us/library/system.windows.controls.primitives.track(VS.90).aspx

thumbSize = (viewportSize/(maximum–minimum+viewportSize))×trackLength

or re-arranging for viewportSize:

viewportSize = thumbSize×(maximum-minimum)/(trackLength-thumbSize)

You've prob found this already but thought I'd post in case others end up here.